The present invention is directed to the treatment of oily contaminated soils, and in particular to bioremediation of oily materials to meet environmentally remediation objectives. As such, the present invention is directed to the treatment of compositions with high petroleum hydrocarbon concentrations, chemically oily based materials or toxic substitutes, examples of which are crude oil or chemical oil storage tank leakage, gasoline station underground storage tank leakage, the underground gasoline pipes leakage, oily soil, oily sludge, chemical sludge, the spills of oily materials on the surface and gradually diffused and deposited in the underground, etc.
Economic and environmental consideration indicates that bioremediation on site offer a significant potential for the remediation and treatment of waste and waste contaminated materials. It maybe note that areas contaminated with hazardous wastes are usually very large, and maybe irregular, requiring the treatment of large amount of solids to meet remediation objectives.
The use of ultimate disposal technologies such as incineration, chemical fixation results in very large expenditures of capital, in addition to the costs associated with the digging out, handling and transporting of these materials to a facility for treatment. Biodegradation methods at site provides a lower cost relative to most other approaches because they are conducted onsite and use less complicated equipment. Furthermore, they can be conducted using a combination of above ground and in situ treatment for a total treatment approach.
One of the common approaches is to use vacuum pumps, or blowers to suck out the contaminated materials in the underground. Apply vacuum blowers to remove the gas phase of oily materials, and spray microorganisms into soil for treating the remained hydrocarbon materials. This approach is energy intensive due to continuously operating vacuum blowers require large amount of electricity, and the result generally cannot meet the remediation objectives.
In situ bioremediation is another way to approach by introducing the mixture of microorganisms into the contaminated field. This approach requires microorganisms to decompose the waste materials through metabolism, the toxic constitutes in the contaminated area are converted into non-toxic constituents or their concentration is reduced such that they no longer pose a threat to the human health and environment. The remediation requires continuous operation and the period of in situ treatment for the site requires years to finish.
One fundamental concern is that the indigenous or cultured microorganisms have no any incentive in that contaminated environment to convert the targeted toxic materials in the soils. The waiting period for the microorganisms to decompose the toxic constitutes is difficult to estimate by field environmental engineers and the remediation result is mixed. For a large field operation, the uncertainty of well-treated and poor-treated fields mixed together can make the on-going field treatment more difficult to proceed.
In the industrial and commercial application, there is a need to have an efficient bioremediation system to take care various types of toxic constitute from contaminated soils. For this reason, there remains substantial room for improvement in the field.